WASHINGTON -- The House has voted to ban the display of Confederate flags at historic federal cemeteries in the deep South.

The low-profile move came Tuesday evening after a brief debate on a measure funding the National Park Service, which maintains 14 national cemeteries, most of which contain graves of Civil War soldiers.

The proposal by Rep. Jared Huffman, D-Calif., added language to block the Park Service from allowing private groups to decorate the graves of southern soldiers with Confederate flags in states that commemorate Confederate Memorial Day. The cemeteries affected are the Andersonville and Vicksburg cemeteries in Georgia and Mississippi.

"The American Civil War was fought, in Abraham Lincoln's words, to 'save the last best hope of Earth,'" Huffman said in a debate in which he was the only speaker. "We can honor that history without celebrating the Confederate flag and all of the dreadful things that it symbolizes."

The flag ban was adopted by a voice vote. The Park Service funding bill is scheduled for a vote on Thursday.

Mark Keel, the chief of South Carolina's State Law Enforcement Division, said Wednesday they're investigating death threats made to South Carolina lawmakers on both sides of the issue, CBS affiliate WLTX reported.

But House leaders have deferred action on a plan by Bennie Thompson, a black Democrat from Mississippi, to ban Confederate images such as that contained in the Mississippi flag from being displayed in the House complex. Numerous statues of Confederate figures such as Jefferson Davis, the president of the Confederate States, are also on display in the Capitol.